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Name _____________________________________ Period _________

*You will need a calculator to complete this homework. *

**Part A **

1. Frequency (speed) of a wave is determine by ____________/____________. This measurement is called ________________________.

2. Calculate the missing values A and B from the following table:

**Frequency **

**A **

1.2 meters/second

**Distance **

3000 meters

**B **

**Time **

150 seconds

30 seconds

A ______________________ B ______________________

**Part B **

Ten students are standing in the Baltimore Harbor watching the start of a marathon. They measure the time difference between seeing smoke and hearing the bang of the starter gun. Their times were:

3.8 seconds

4.2 seconds

3.8 seconds

4.0 seconds

4.4 seconds

3.8 seconds

4.0 seconds

3.6 seconds

4.2 seconds

4.2 seconds

1. The average time for the group is ___________________________.

2. Calculate the distance from the students to the Baltimore Harbor starting line, if the speed of sound is 340 meters/second.

X average time in seconds

= 340 meters/second

The distance from the group to the starting gun in meters (X) = _____________________

**Part C **

1. A diver 4.5 kilometers (km) away from a diving boat hears the warning siren 3 seconds after it actually rang. What is the speed of sound under water? Show work below:

2. A person at the mouth of a cave shouts, and hears an echo from the back wall of the cave. Using a stopwatch, she times 1 second between shouting and hearing the echo.

Calculate how far away she is from the back wall of the cave. The speed of sound is 340 meters per second (m/s).

3. A source produces 400 waves every minute (1 minute = 60 seconds). If the speed of the waves is 8 mm/second (millimeters per second), calculate the distance between each trough.

**Part D **

1. Give an example showing that waves can travel through solids. _________________________

__________________________________________________________________________________________

2. Give an example showing that waves can travel through gas. _________________________

__________________________________________________________________________________________

3. In the Star Wars films, there are many loud explosions as spaceships blow up. In reality, you wouldn’t hear the explosions at all. Why not? ______________________________________________

__________________________________________________________________________________________